2/See "List of Metropolitan Status/Rank/Size Codes" for documentation of codes.

3/The Census 2000 data have been tabulated for 1980 metropolitan definitions to provide more comparability over time. The standards used to define metropolitan areas changed substantially in 1983, creating large differences between the 1980 Census metropolitan area data and the 1990 Census metropolitan area data. In particular, the number of central cities markedly increased, and it became possible for much smaller cities to be designated as central cities. To address this comparability issue, the 1990 Census Transportation Planning Package National tabulations included data not only for the then-current metropolitan definitions, but also some 1990 census data tabulated in terms of the 1980 metropolitan definitions. This practice has been followed in the Census 2000 CTPP as well, resulting in a time series based on comparable metropolitan definitions with data from the 1980, 1990, and 2000 censuses. This dataset only includes the Census 2000 data, tabulated for 1980 metropolitan definitions in the ccs_80 geographic field.